The interaction specificities of nucleic acids of various base compositions to a variety of molecules, e.g., reporter molecules, peptides and basic proteins, is under investigation. It is hoped that highly selective systems, i.e., compounds with high affinity to a particular base pair site, can be synthesized. The ultimate aim of this work is to understand the mechansim of protein-nucleic acid recognition process. BIBLIOGRAPHIC REFERENCES: L. Kapicak and E.J. Gabbay, "The Effect of Aromatic Cations on the Tertiary Structure of DNA", J. Am. Chem. Soc., 97, 403 (1975). J. Reuben and E.J. Gabbay, "Binding of Manganese (II) to DNA and the Competitive Effects of Metal Ions and Organic Cations. An EPR Study", Biochemistry, 14, (1975).